In recent years, gardening and flower arrangement have become popular, a large number of associated publications such as books and journals even for common readers have been published, and numerous flower arrangement classes and contests have been held. Such circumstances result in various needs in the flower market in such a way that various types of flowering plants are demanded.
Among a huge variety of flower plants, Dianthus caryophyllus (carnation) is widely used in bouquets and in flower arrangement and is proudly enjoying the second place in shipment amount with the first place won by chrysanthemum (according to the 2002 statistics by the Ministry of Agriculture, Forestry and Fisheries of Japan). Carnation is such a familiar flower as described above. On the other hands, carnation encounters demand for the various breeds including: new breeds unique in color and novel in type; breeds resistant to wilt; breeds free from calyx splitting and capable of being shipped in a period where the unit price thereof is high; and breeds allowing ample annual harvesting of flowers; and early season spray breeds.
Accordingly, for the purpose of meeting the various needs in the market, breed improvement based on hybridization and the like has been widely practiced. Examples of such breed improvement include a case where a transgenic carnation plant having a flower color modified by using biotechnology (see National Publication of International Patent Application No. 11-505116).